#include "type.h"
#include "const.h"
#include "protect.h"
#include "proto.h"
#include "proc.h"
#include "global.h"

PRIVATE void init_idt_desc(unsigned char vector, u8 desc_type,
	int_handler handler, unsigned char privilege);
	
PRIVATE void init_descriptor(DESCRIPTOR * p_desc, u32 base, u32 limit, u16 attribute);
	
void divide_error();
void single_step_exception();
void nmi();
void breakpoint_exception();
void overflow();
void bounds_check();
void inval_opcode();
void copr_not_available();
void double_fault();
void copr_seg_overrun();
void inval_tss();
void segment_not_present();
void stack_exception();
void general_protection();
void page_fault();
void copr_error();
void hwint00();
void hwint01();
void hwint02();
void hwint03();
void hwint04();
void hwint05();
void hwint06();
void hwint07();
void hwint08();
void hwint09();
void hwint10();
void hwint11();
void hwint12();
void hwint13();
void hwint14();
void hwint15();

PUBLIC void init_prot()
{
	init_8259A();
	init_idt_desc(INT_VECTOR_DIVIDE, DA_386IGate, divide_error, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_DEBUG, DA_386IGate, single_step_exception, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_NMI, DA_386IGate, nmi, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_BREAKPOINT, DA_386IGate, breakpoint_exception, PRIVILEGE_USER);
	init_idt_desc(INT_VECTOR_OVERFLOW, DA_386IGate, overflow, PRIVILEGE_USER);
	init_idt_desc(INT_VECTOR_BOUNDS, DA_386IGate, bounds_check, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_INVAL_OP, DA_386IGate, inval_opcode, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_COPROC_NOT, DA_386IGate, copr_not_available, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_DOUBLE_FAULT, DA_386IGate, double_fault, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_COPROC_SEG, DA_386IGate, copr_seg_overrun, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_INVAL_TSS, DA_386IGate, inval_tss, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_SEG_NOT, DA_386IGate, segment_not_present, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_STACK_FAULT, DA_386IGate, stack_exception, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_PROTECTION, DA_386IGate, general_protection, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_PAGE_FAULT, DA_386IGate, page_fault, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_COPROC_ERR, DA_386IGate, copr_error, PRIVILEGE_KRNL);
	
	init_idt_desc(INT_VECTOR_IRQ0 + 0, DA_386IGate, hwint00, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 1, DA_386IGate, hwint01, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 2, DA_386IGate, hwint02, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 3, DA_386IGate, hwint03, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 4, DA_386IGate, hwint04, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 5, DA_386IGate, hwint05, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 6, DA_386IGate, hwint06, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 7, DA_386IGate, hwint07, PRIVILEGE_KRNL);
	
	init_idt_desc(INT_VECTOR_IRQ8 + 0, DA_386IGate, hwint08, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 1, DA_386IGate, hwint09, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 2, DA_386IGate, hwint10, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 3, DA_386IGate, hwint11, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 4, DA_386IGate, hwint12, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 5, DA_386IGate, hwint13, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 6, DA_386IGate, hwint14, PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 7, DA_386IGate, hwint15, PRIVILEGE_KRNL);
	
	init_idt_desc(INT_VECTOR_SYS_CALL, DA_386IGate, sys_call, PRIVILEGE_USER);

	memset(&tss, 0, sizeof(tss));
	tss.ss0 = SELECTOR_KERNEL_DS;
	init_descriptor(&gdt[INDEX_TSS], vir2phys(seg2phys(SELECTOR_KERNEL_DS), &tss), sizeof(tss) - 1, DA_386TSS);
	tss.iobase = sizeof(tss);
	
	int i;
	PROCESS* p_proc = proc_table;
	u16 selector_ldt = INDEX_LDT_FIRST << 3;
	for (i = 0; i < NR_TASKS; i++)
	{
		init_descriptor(&gdt[selector_ldt >> 3], vir2phys(seg2phys(SELECTOR_KERNEL_DS), proc_table[i].ldts),
				LDT_SIZE * sizeof(DESCRIPTOR) - 1, DA_LDT);
		p_proc++;
		selector_ldt += 1 << 3;
	}

}

PUBLIC void init_idt_desc(unsigned char vector, u8 desc_type,
	int_handler handler, unsigned char privilege)
{
	GATE *p_gate = &idt[vector];
	u32 base = (u32) handler;
	p_gate -> offset_low = base & 0xFFFF;
	p_gate -> selector = SELECTOR_KERNEL_CS;
	p_gate -> dcount = 0;
	p_gate -> attr = desc_type | (privilege << 5);
	p_gate -> offset_high = (base >> 16) & 0xFFFF;
}

PUBLIC u32 seg2phys(u16 seg)
{
	DESCRIPTOR* p_dest = &gdt[seg >> 3];
	return (p_dest -> base_high << 24) | (p_dest -> base_mid << 16) | (p_dest -> base_low);
}

PRIVATE void init_descriptor(DESCRIPTOR *p_desc, u32 base, u32 limit, u16 attribute)
{
	p_desc -> limit_low = limit & 0x0FFFF;
	p_desc -> base_low = base & 0x0FFFF;
	p_desc -> base_mid = (base >> 16) & 0x0FF;
	p_desc -> attr1 = attribute & 0xFF;
	p_desc -> limit_high_attr2 = ((limit >> 16) & 0x0F) | (attribute >> 8) & 0xF0;
	p_desc -> base_high = (base >> 24) & 0x0FF;
}

PUBLIC void exception_handler(int vec_no, int err_code, int eip, int cs, int eflags)
{
	int i;
	int text_color = 0x74;
	
	char  err_description[][64] = {
		"#DE Divide Error",
		"#DB RESERVED",
		"—  NMI Interrupt",
		"#BP Breakpoint",
		"#OF Overflow",
		"#BR BOUND Range Exceeded",
		"#UD Invalid Opcode (Undefined Opcode)",
		"#NM Device Not Available (No Math Coprocessor)",
		"#DF Double Fault",
		"    Coprocessor Segment Overrun (reserved)",
		"#TS Invalid TSS",
		"#NP Segment Not Present",
		"#SS Stack-Segment Fault",
		"#GP General Protection",
		"#PF Page Fault",
		"—  (Intel reserved. Do not use.)",
		"#MF x87 FPU Floating-Point Error (Math Fault)",
		"#AC Alignment Check",
		"#MC Machine Check",
		"#XF SIMD Floating-Point Exception"
	};
	
	disp_pos = 0;
	
	for (i = 0; i < 80 * 5; i++) 
	{
		disp_str(" ");
	}
	
	disp_pos = 0;
	disp_color_str("Exception! -->", text_color);
	disp_color_str(err_description[vec_no], text_color);
	disp_color_str("\n\n", text_color);
	disp_color_str("EFLAGS:", text_color);
	disp_int(eflags);
	disp_color_str("CS:", text_color);
	disp_int(cs);
	disp_color_str("EIP:", text_color);
	disp_int(eip);
	
	if (err_code != 0xFFFFFFFF)
	{
		disp_color_str("Error code:", text_color);
		disp_int(err_code);
	}
}
